Shock absorber



SHOCK ABSORBER Filed Dec. l0, 1956 2 Sheets-Sheet l myn ATTORNEY R. C. MASON SHOCK ABSORBER April 12, 1938.`

.wfg 6. L

Filed De. lO, 1936 2 Sheets-Sheet 2 INVENTOR @Mayr C. Maso/2 III i ATTORNEY Patented Apr. 12, 1938 UNITED STATES PATENT foFFlcE* RichadHznlI-solo'l Okla.

s claims.

This invention relates to shock-absorbers and more particularly to a shock-absorber adapted for use in connection with well drilling and pumping machinery.

In pump oil wells a walking beam is usually employed for raising the rods in a well with a predetermined length of stroke, while gravity is lused for returning the rods to the bottom of the well for pumping oil to the surface of the ground.

The operation of changing the direction of travel of the rods requires a great deal of power to check the inertia on the Ydown stroke thereof and the rapid checking of travel of the rods often causes buckling and breakage of the rods, or other damage to the machinery.

It is, therefore, the principal object of the present invention to provide a shock-absorber for efciently checking the inertia on the down stroke of rods in an oil well and to eiectively absorb n the shocks and jars incidental to well pumping operations.

Other important objects of the present invention are to reduce the power required for changing direction of travel of rods in an oil well and,

.17, therefore, reduce the cost of operation of pumping apparatuses; to provide air as a cushion for use in the shock-absorber; to provide for regulating the volume of air to be used as al cushion; to provide for suspending the shock-absorber over :xn a well hole whereby a straight-lift of the rods may be effected while using the shock-absorber; and to provide for a full length stroke of the walking beam for increasing the pumping capacity of the well.

:B5 In accomplishing these and other objects of the present invention, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings,

wherein: I

-10 Fig. l is a vertical elevational view of an oil well derrick and walking beam showing a shockabsorber embodying the features of the present invention mounted in the derrick and actuated- .by the Walking beam. 45 Fig. 2 is a vertical cross-section showing the detail construction of the shock-absorber.

Fig. 3 is a horizontal cross-section on the line 3 3, Fig. 2.

Fig. 4 is a horizontal cross-section on the line 50 4-4, Fig. 2.

Fig. 5 is a detail elevational view of the pump for supplying air to the shock-absorber, the pump being positioned for a short stroke.

Fig. 6 is a vertical elevational view of an oil 55 well derrick provided with a modified form of (Cl. Z55-16) shock-absorber showing the addition of a weight as a part of the shock-absorber for counterbalancing the Weight of the rods.

Fig. '7 is a. vertical cross-section through the upper end of the modified form of shock-absorber 5 showing its detail construction.

Referring more in detail to the drawings:

I designates a derrick such as is customarily placed over an oil well hole, forpulling rods, or tubing, or otherwise servicing a well after it ls 10 drilled. The well hole is provided with the usual outlet fittings 3 and polish rod 4 extending upwardly therefrom for engagement by a coupling 5 connecting the polish rods to a walking beam 6 through a connecting link 1. The walking beam 15 is centrally fulcrumed over the Samson post 8 on conventional center irons 9, the post 8 having a seat I0 for limiting the upward movement of the working end II of the walking beam, when not in use. A conventional pitman I2 is also provided 20 for actuating, the walking beam by means of a power unit not shown.

The principal feature of the present invention comprises the shock-absorber I3, and the pump I4 for providing the shock-absorber with working 25 medium, such as air, to be used as a cushion.

The shock-absorber I3 is suspended centrally over the well hole bysuspension cables I5 which are suitably secured to the derrick at their upper ends, as at I6, the cables being mounted at their 30 other ends ln loops I1, preferably four in number,4 equidistantly spaced around an internally threaded collar I8.

The body of the shock-absorber preferably consists of a piece of well casing to form a container 35 I9 screwed into the collar I8 for extension downwardly in the direction of the well hole,"the container also being provided with external threads at its lower end for receiving the internal threads of a collar which is also provided with loops 40 2|.- Tie-down cables 22 are passed through the loops 2| for extension to the base 23 of the derrick for anchoring the shock-absorber in position.

The collar 20 is provided with a central bore in which is mounted a packing gland 24, 45 through which a polish rod is extended for connection with the uppermost polish rod 26 of the well pull-rods through the coupling 21. The rod 25 is provided at its upper end with a series of packing rings, or' cups 28 having close sliding 50 t in a Working barrel 29 threadedly mounted in a reduced end 30 of a swedge nipple 3l, the nipple 3l having external threads for mounting same in the upper end of the collar I8.l The working barrel 29 extends substantially the 55 A length of the casing I9 and the lowerend thereof is braced against lateral movement by guide lugs I9' which are suitably fixed to the inner wall of the container I9. The upper end of the Working barrel is threadedly mounted in upset relation to the upper end of the nipple to provide Vthreads above the nipple for threadedly mounting a coupling collar 32. A sleeve 33 having a iiared lower end 34 for receiving the upper end 35 of the working barrel polish rod is mounted in the coupling 32 by a plugged end 36 to seal the upper end of the nipple 3l during normal operating conditions except for the breather holes 36' leading from the working'barrel which prevent the formation of a vacuum in the upper end of the working barrel. Upward movement of the polish rod is checked by compression of air in the sleeve 33 by the end of the polish rod 35 and upon engagement of the rings 28 with the sleeve should gravity pressure on the rods suddenly be released.

Provided in the collar I8 preferably below the loops thereof is a working medium inlet opening 31 and an outlet opening 38 having internal threads for mounting the threaded end 39 of a pop-oi? valve 40. An inlet valve 4I is also provided for threaded engagement in the inlet opening 31 and is connected by a flexible hose, or the like, 42 with the lower end of the pump I4, as shown at 43.

The pump I4 is preferably mounted on the Samson post 8 for pivotal engagement therewith, as shown at 44, and consists of a casing 45 having a plunger 46 therein, the plunger 46 being pivotally mounted on the walking beam, as shown at 4l, whereby rocking motion of the beam reciprocates the plunger for forcing air through the exible tube into the casing I9, the casing I9 having been previously filled to a suitable level with a working medium such as oil, or the like, 48 for receiving the initial action of the packing rings 28 in' the working barrel in response to reciprocation of the rods in the oil well.

With the working medium, such as oil, in the casing I3 at a predetermined level andthe remainder of the casing lled with working medium, such as air delivered by the pump, to act as a cushion, it is sometimes desirable to either shorten the length of stroke of the pump, or disconnect it altogether.

I, therefore, provide a bracket 49 on the under side of the Walking beam above the pivotal connection of the pump casing. The bracket 49 is provided with a horizontal bar portion 50 and the pump plunger is provided with a suitable bearing 5I engageable and movable on the .bar for varying the length of stroke of the pump to vary the amount of air, or other medium, produced by the pump, when a variation is desired in relation to the predetermined pressure of air desired in the shock-absorber casing.

In operating an apparatus constructed as described, `oil, or other working medium, is first placed in the casing I9 through thehole at the upper end of the nipple 3I to a level approximately half the length of the casing, after which the casing is sealed by the plug 36. The walking beam is then actuated by a prime mover, not shown, which lifts the rods 4 upwardly when the outer end of the walking beam is raised and at the same time partially withdraws the plunger 46 from the casing 45 of -the pump. Reverse movement of the walking beam returns the rods 4 to the other end of its stroke and forces working medium from the pump thro ugh the hose 42 into the upper end of the shock-absorber casing to ll that portion of the casing with compressed working medium at a pressure determined by the outlet valve 40.

It may be here pointedout that the pumwhile preferably actuated by the Walking beam, may be positioned conveniently elsewhere, for example, on the derrick or ring, in which case other motive power could be suitably applied.

When the rods are raised, the packing rings 2B are moved upwardly in the working barrel 29, the level of oil in the casing being lowered to reduce pressure in the air compartment of the container. When, however, the direction of travel of the rods is reversed, the 'great weight thereof is aiected by gravity to cause great speed, power and inertia in a downward direction. The oil in the working barrel is, therefore, forced out of the barrel and back into the container I9 where it is stopped with a cushioning effect upon compression of the air in the casing to cushion the jarring eiect of the rods in the well and produce the effect of retarding downward motion and lifting them back in an upward direction to relieve the walking beam of the tremendous power required to alone change the direction of travel of the rods. Another advantageouseiect produced by my improved shock-absorber is that a full length stroke of the walking beam may be used as a consequence of lreduction in power necessary to change direction of travel of the rods due to the lift provided by the air cushion in the shock-absorber. y

In Fig. 6 I have shown a modified form of shock-absorber wherein a counterbalance weight 52 is mounted on the side of the derrick 53, the counterbalance weight being provided with a iiexible connection 54 extending over pulleys 55 mounted on a sub-crown block 56 suitably positioned on the derrick. The end of the iiexible connection opposite the counterbalance is fixed to a polish rod 51 by a coupling 58, the polish rod 51 extending into the working barrel 59 of a shock-absorber 60 similar to the one described in the preferred form of the invention.

'Ihe operation of my modified form of invention is substantially similar to that previously described with the exception that the counterbalance alleviates part of the need for compression of the air.

What I claim and desire to secure by Letters Patent is:

1. A shock-absorber including a container, means closing the ends of the container, a working barrel mounted in one of said closing means, a polish rod mounted in the other of said closing meanszl extending into said working barrel, said polish rod having cups engageable with said working barrel, said container having a working medium compresslble in response to movement of said rod in said working barrel for checking inertia incidental to downward movement of said rod, means for supplying working medium to said container including a iiuid pump having communication with said container, and means for venting excess duid-pressure from said con- A tainer.

2. A shock-absorber for the rods of a well including in combination with means for supporting said rods in said well, a closed container mounted on said supporting means having a working barrel, a polish rod having cups mounted in said working barrel and having one end extending through one end of said container, said end being connected with the well rods, a working medium partially filling said container and sealing the cups in said working barrel, a working medium lling the remainder of said container, and means for supplying said second named working medium to said container, said rst named working medium acting on said second named working medium in response to downward movement of said cups incidental to downward movement of said rods in said well to compress same for absorbing shock of said rods at the end of their stroke in the well.

3. A shock-absorber for the rods of a well including in combination with means for supporting said rods in said well and means for reciprocating the rods in the well, a closed container mounted on said supporting means having a working barrel, a polish rod having cups mounted in said working barrel and having one end extending through one end of said container, said end being connected with the well rods, a working medium partially lling said container and sealing the cups in said working barrel, a working medium lling the remainder of Asaid container, and means operated by said reciprocating means for supplying said second named working medium to said container, whereby said first named working vmedium acts on said second named working medium in response to downward movement of said cups incidental to downward movement of said rods in said well to compress same for absorbing shock of said rods at the end of their stroke in the well.

4. A shock-absorber for the rods of a well including in combination with means for supporting said rods in said well and means for reciprocatingthe rods in the well, a closed container mounted on said supporting means having a removably mounted working barrel, a polish rod having cups mounted in saidworking barrel and having one end extending through one end of said container,

said end being connected with the well rods, a working medium partially iilling said container and sealing the cups in said working barrel, a

working medium filling the remainder of said container, and means mounted on said reciprocating means and operable thereby communicating with said container for supplying said second named working medium to said container, whereby said rst named working medium acts onvsaid second named working medium in response to downward movement of said cups incidental to downward movement of said rods in said well to compress same for absorbing shock of said rods at the end of their stroke in the wel 5. A shock-absorber for the rods of a well including in combination with means for supporting said rods in said well and means for reciprocating the rods in the well, a closed container mounted on said supporting means having a removably mounted working'barrel, a polish rod having cups mounted in said working barrel and having one end extending through one end of said container, said end being connected with the well rods, a working medium partially lling said container and sealing the cups in said working barrel, a working medium filling the remainder of said container, means mounted on said reciprocating means and operable thereby communicating with said container for supplying said second named working medium to said container. whereby said first named working medium acts on said second named working medium in response to downwardmovement of said cups incidental to downward movement of said rods in said well to compress same for absorbing shock of said rods at the end of their stroke in the well, and l means for venting excess pressure in said container.

6. A shock-absorber for the rods of a Well including in combination with means for sup- I L porting said rods in said well and means for re-.- ciprocating the rods inthe well, a closed con-jf tainer mounted on said supporting means having a removably mounted working barrel, a polish" rod having cups mounted in said working barrel and having one end extending through one end of said container, said end being connected with dental to downward movement of lsaid rods in said Welll to compress same for absorbing shock of said rods at the end of their stroke :inthe Well, means for venting excess pressure `in'saidcontainezg and means for regulating quantity of working medilum supplied to said container by said supply '1. A shock-absorber for the rods of a well including in combination with means for supporting said rods in said well and means for reciprocating the rods in the Well, a closed container mounted on said supporting means having a .removably mounted working barrel, a polish rod having ,cups mounted in said vworking barrel and having one end extending through one end of said container, said end being connected withthe well rods, means for hunting upward movement of said rod in said working barrel,l a working medium partially lling said containerand sealing the `cups in said working barrel, a working mediuml filling the remainder of said container, vmeans mounted on said reciprocating means and operable thereby communicating with said container for supplying said second named workingffmedium to said container, whereby said rst `n amed working medium acts on said second named working medium in response to downward movement of said cups incidental to down'ward'lmovement of said rods in said well v to compress .same for absorbing shockof said rods atthe end of theirr stroke in the well, means for venting excess pressure in said container, `and means Vfor regulating quantity of working mediums'upplied to saidcontainer by said supply means.

8. In combination with the rods of a well, a support therefor, and means for reciprocating the rods in the well; a shock-absorber for checking inertia of the rods upon change in direction of reciprocation thereof including a container having means closing the ends thereof, and a tubular member mounted in said container and adapted to receive one of said rods, said rod having packing members engageable with said tubular member, said container having a working medium compressible incidental to relative movement between said rod and tubular member and having a working medium for sealing the rod relative to said compressible working medium.

RICHARD C. lMASON. 

